Information Technology Review - Auditing Information Systems: Enhancing Performance of the Enterprise - page 50

There are different types of networks which can be used to access various resources.
Local area networks (LAN) are used to connect computers and other associated
devices within an office environment. A LAN could be used by a few users to thou-
sands of users in an office complex. A metropolitan area network (MAN) would be
set up where users are spread over various offices in a town or city. Office LANs in a
city or town can be linked up to form a MAN. On a larger scale where an enterprise
has branch offices over long distances, such as intercity or across countries, such net-
works are referred to as wide area networks (WAN).
Different types of network technologies are used to connect computers, LANs, MANs,
and WANs. In offices, you will come across Ethernet cables which have speed ran-
ging from 100 mbps to 1,000 mbps. These are usually copper cables which link com-
puters and network servers via Ethernet ports.
Fibre optic cables, which consist of glass strands and use light to transmit data, are also
used to form LANs and larger networks such as MANs and WANs. Fibre networks
are faster than Ethernet networks in terms of data speeds. Data transfer speed of 1
mbps or more are possible on fibre networks.
Wireless technologies can also be used to implement networks such as LANs or MANs.
Wireless networks use radio technologies such as Wi-Fi. Wireless technologies can
also be used to connect office equipment such as printers, scanners, and photocopies.
Enterprises should take interest in ensuring that networks are secured using various se-
curity technologies because of the important function networks serve. Key among
the various functions is the central storage of data and also the ability to share re-
sources among many users. We will review in detail issues relating to network secur-
ity in chapter 7.
IS auditors should review the network infrastructure in order to ensure that network re-
sources are protected from both internal and external threats. Audit objectives for
auditing networks are many, and we will review these objectives below by looking
at individual network devices which are used to design and develop computer net-
works.
b) Network Firewalls
Firewalls are used to protect internal enterprise resources, such as data, information, and
servers, from external threats. There are thousands of hackers out there waiting for
an opportunity to exploit vulnerabilities on firewalls. Firewalls play a very important